Comment # 18 on bug 1199355 from Stefan Seyfried

I managed to build a seemingly working 8.0.1 version in home:seife:testing.

I can get a backtrace now:

PID: 2032   TASK: ffff481f84063f80  CPU: 3   COMMAND: "qemu-system-aar"
 #0 [ffff80000b46a7c0] machine_kexec at ffffcbfbb6bb99b0
 #1 [ffff80000b46a7f0] __crash_kexec at ffffcbfbb6d1885c
 #2 [ffff80000b46a980] crash_kexec at ffffcbfbb6d18998
 #3 [ffff80000b46a9a0] die at ffffcbfbb6ba1b08
 #4 [ffff80000b46aa50] die_kernel_fault at ffffcbfbb790d5f8
 #5 [ffff80000b46aaa0] do_page_fault at ffffcbfbb7932a90
 #6 [ffff80000b46ab00] do_translation_fault at ffffcbfbb7932d68
 #7 [ffff80000b46ab20] do_mem_abort at ffffcbfbb6bbcac8
 #8 [ffff80000b46ab50] el1_abort at ffffcbfbb791f494
 #9 [ffff80000b46ab80] el1h_64_sync_handler at ffffcbfbb7920d80
#10 [ffff80000b46acc0] el1h_64_sync at ffffcbfbb6b91b0c
#11 [ffff80000b46ace0] blk_mq_submit_bio at ffffcbfbb712f914
#12 [ffff80000b46ad80] __submit_bio at ffffcbfbb711e884
#13 [ffff80000b46adc0] submit_bio_noacct at ffffcbfbb711ead8
#14 [ffff80000b46ae10] submit_bio at ffffcbfbb711eb90
#15 [ffff80000b46ae40] __swap_writepage at ffffcbfbb6ecc330
#16 [ffff80000b46aef0] swap_writepage at ffffcbfbb6ecc66c
#17 [ffff80000b46af20] pageout at ffffcbfbb6e62ed0
#18 [ffff80000b46afc0] shrink_page_list at ffffcbfbb6e637bc
#19 [ffff80000b46b0b0] shrink_lruvec at ffffcbfbb6e67750
#20 [ffff80000b46b220] shrink_node at ffffcbfbb6e680f4
#21 [ffff80000b46b2b0] do_try_to_free_pages at ffffcbfbb6e68818
#22 [ffff80000b46b330] try_to_free_pages at ffffcbfbb6e69f44
#23 [ffff80000b46b3e0] __alloc_pages at ffffcbfbb6ec0564
#24 [ffff80000b46b530] alloc_pages at ffffcbfbb6ee8e68
#25 [ffff80000b46b560] folio_alloc at ffffcbfbb6ee8f44
#26 [ffff80000b46b580] filemap_alloc_folio at ffffcbfbb6e44594
#27 [ffff80000b46b5b0] page_cache_ra_unbounded at ffffcbfbb6e58ff8
#28 [ffff80000b46b650] ondemand_readahead at ffffcbfbb6e59528
#29 [ffff80000b46b690] page_cache_async_ra at ffffcbfbb6e59770
#30 [ffff80000b46b6c0] filemap_get_pages at ffffcbfbb6e49204
#31 [ffff80000b46b770] filemap_read at ffffcbfbb6e49494
#32 [ffff80000b46b8a0] generic_file_read_iter at ffffcbfbb6e497f0
#33 [ffff80000b46b8f0] xfs_file_buffered_read at ffffcbfb669ece90 [xfs]
#34 [ffff80000b46b920] xfs_file_read_iter at ffffcbfb669ed1a4 [xfs]
#35 [ffff80000b46b950] io_read at ffffcbfbb6fc8ae4
#36 [ffff80000b46ba70] io_issue_sqe at ffffcbfbb6fcd1b4
#37 [ffff80000b46bb30] io_submit_sqes at ffffcbfbb6fcf188
#38 [ffff80000b46bc20] __arm64_sys_io_uring_enter at ffffcbfbb6fd09e0
#39 [ffff80000b46be10] invoke_syscall at ffffcbfbb6baa824
#40 [ffff80000b46be40] el0_svc_common.constprop.0 at ffffcbfbb6baaa2c
#41 [ffff80000b46be70] do_el0_svc at ffffcbfbb6baaa64
#42 [ffff80000b46be80] el0_svc at ffffcbfbb791f8cc
#43 [ffff80000b46bea0] el0t_64_sync_handler at ffffcbfbb7920f10
#44 [ffff80000b46bfe0] el0t_64_sync at ffffcbfbb6b91e34
     PC: 0000ffff9f2d9c28   LR: 0000ffff9f8420c4   SP: 0000ffff9df6dbf0
    X29: 0000ffff9df6dc10  X28: 0000000000001022  X27: 0000aaaafaad564c
    X26: 000000000080e1c0  X25: 0000aaaadd4dbcf2  X24: 0000aaaadd4def38
    X23: 0000fffda8005770  X22: 0000fffda8005688  X21: 0000fffda8005680
    X20: 0000000000000000  X19: 0000fffd9d7658f0  X18: 0000000000000001
    X17: 0000ffff9f2d9c00  X16: 0000ffff9f85ffc8  X15: 0000000000000000
    X14: 0000000000000000  X13: 0000ffff90013420  X12: 0000ffff900342a0
    X11: 00ffffffffffffff  X10: 0038af1bcc5c671f   X9: 0000000000000004
     X8: 00000000000001aa   X7: 0000000000000000   X6: 0000000000000000
     X5: 0000000000000008   X4: 0000000000000000   X3: 0000000000000000
     X2: 0000000000000000   X1: 0000000000000004   X0: 000000000000001d
    ORIG_X0: 000000000000001d  SYSCALLNO: 1aa  PSTATE: 40001000

However, that's about what's left of my crashdump-examination knowledge ;-)

Could you advise me how to gather useful information to find the cause of the
crash?